1. Field of the Invention
This invention relates in data processing and more specifically for a filter for image data up sampling.
2. Description of the Related Art
In some examples of spatial scalable video coding, predictions between different coding layers are utilized to improve performance. In particular, inter layer prediction from a lower resolution base layer to a higher resolution enhancement layer may be utilized for improving coding efficiency on the enhancement layer. Texture inter layer prediction may be done by up sampling using a low-pass filter to avoid aliasing and imaging. Currently, a fixed filter with a one dimensional (1D) 6-tap filter component may be used for low pass filtering.
A filter with a 1D 4-tap filter component may be utilized for re-sampling. However, these conventional filters do not provide the same or nearly the same coding efficiency as a filter with a 1D 6-tap filter component.
Extended Spatial Scalability (ESS) has been implemented to unite dyadic (power of 2) and non-dyadic image resolution re-sampling. To remove the phase shift of dyadic resampling, luma down-sampling is performed at ½ phase and up sampling is performed at +¼ phase and −¼ phase. The 1D 6-tap filter component utilizes coefficients of [1, −4, 28, 9, −2, 0] for the +¼ phase and coefficients of [0, −2, 9, 28, −4, 1] for −¼ for both the horizontal and vertical dimensions of two dimensional (2D) images.
What is desired is an improved filter for image data up sampling.
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